Technical Field
The present invention relates to an apparatus and method for producing a (metal plate)-(ceramic board) laminated assembly, and an apparatus and method for producing a power-module substrate, used for producing a power-module substrate for a semiconductor device controlling large electric current and high voltage.
Priority is claimed on Japanese Patent Application No. 2013-72421, filed Mar. 29, 2013, the content of which is incorporated herein by reference.
Background Art
It is known as a conventional power-module substrate in which a circuit board is bonded to one surface of a ceramic substrate in a laminated state and a heat-radiation plate is bonded on the other surface of the ceramic substrate in a laminated state. It is used as a power module by soldering electronic components such as a semiconductor chip (a power device) and the like on the circuit board and bonding a heat sink on the heat-radiation plate.
For such a power-module substrate, there is technics described in Patent Document 1 or Patent Document 2, for example, as a method of bonding metal plates to be a circuit board or a heat-radiation plate on a ceramic substrate in a laminated state.
In Patent Document 1, it is disclosed that: a copper-circuit assembly is coordinated in a state in which circuit elements are connected to each other by thin bridge portions; bonding material such as Ag—Cu—Ti including active metal such as Ti is printed on a ceramic substrate in advance with a shape pattern of the copper-circuit assembly; these are laminated and heated so as to be bonded; and then the bridge portions are removed by an etching process.
In Patent Document 2, a method is disclosed for producing substrates for power modules by: laminating a ceramic base-material and a metal plate with a brazing-material foil therebetween and bonding them; then etching the metal plate so as to form a circuit pattern; forming grooves between the circuit pattern on the ceramic base-material; and separating the ceramic base-material along the grooves.
In Patent Document 3, it is performed that: a brazing-material foil is pasted on one surface of a metal flat-plate with a resin-coating layer (including octanediol as an organic resin) therebetween in advance; these overlapped metal flat-plate and brazing-material foil are punched and formed into an outer shape of a circuit layer; the brazing-material foil pasted on the circuit layer is laminated on a ceramic flat-plate; and then the circuit layer and the ceramic flat-plate are laminated and bonded by the brazing-material foil therebetween.